The Italian Communist Party, stung by recent electoral defeats that put in question its reputation as the most successful communist movement in the West, empowered a special commission today to prepare proposals for an extraordinary party congress aimed at revitalizing the party.

Political observers said the decision to hold such a congress a year ahead of schedule and to assign its preparation to a 70-member commission, instead of leaving it to the party's top leadership as in the past, reflected a state of turmoil among the Communists.

The decision came at the end of a closed three-day meeting of the party's Central Committee. According to a senator who attended, the state of the movement was hotly debated and, by implication, the year-old leadership of Alessandro Natta was questioned.

The issues under debate, said the senator, were two electoral failures this year, the party's apparent "identity crisis" and its isolation after two years of government by a five-party coalition under Socialist Prime Minister Bettino Craxi.

"We all agreed that things have to change," the senator said. "What we couldn't agree on was how. That will now be left to the party congress to determine."

The Central Committee meeting culminated a period of public soul-searching initiated by Natta after the defeat in June of a Communist-proposed referendum. The party unsuccessfully challenged Craxi's plan to end automatic pay raises tied to the cost of living.

While in 1976 34.5 percent of the electorate voted Communist, and the party controlled most large cities, the party won just under 30 percent of the vote in 1983. Its vote in May provincial elections was only slightly higher. The failure to rally even the working class was a shock to the party, which is still the largest communist party in the West.

Analysts say the problem of the Communists is that since the advent of the first non-Christian Democratic prime ministers in the 1980s, the party no longer attracts voters as a sole viable alternative to Christian Democrats -- who had been dominant since World War II.

When the Communist Party's fortunes were at their height under general secretary Enrico Berlinguer in the 1970s, even the Christian Democrats began to believe in the inevitability of power-sharing with the Communists.

All that changed in the 1980s when the Socialist Party, under the leadership of Craxi, broke out of its own ideological isolation to play a role as a power broker between the larger Christian Democratic and Communist parties.

"The Communist problem is simply that today Italian voters understand there are alternatives to Communist and Christian Democratic rule," said Paolo Garimberti, the Rome editor of the daily La Stampa. "That has left the Communists isolated and alone. Until they can find a way of forging alliances with the Socialists, whom they now just attack, or some other natural political ally, they will remain in the wilderness."

Natta, 67, a bland former high school tracher, was elected to head the party after the death in June 1984 of the charismatic Berlinguer.

While Natta inherited the party when its fortunes were already showing signs of decline, he has been blamed by many party stalwarts for the recent sense of drift shown in the two electoral tests this year.

Responding to internal pressures, Natta called for an open debate to "reflect on our policies."

In response, leader after leader offered interviews in the national press to air their opinions, underlining that the party was deeply split about its future and even the present.

Luciano Lama, the head of the powerful Communist labor federation, complained in print that "there is a loss of imagination, of contact with reality and the problems of Italian society that concerns the whole Italian Communist Party."

The level of criticism was such that Natta was on the defensive when he addressed the Central Committee Monday. He reportedly called for a return to the party's traditional "democratic centralism," meaning disciplined acceptance of leadership decisions.

That, according to various participants in the meeting, did not still the criticism. Natta and his leadership reportedly were criticized for not having understood the electoral defeats, for not generating policies that would make the party more attractive to new voters, and for not coming up with viable political alternatives that would make the party a credible force to govern.

By these accounts, the leadership was criticized for failing to form alliances with what were described as natural allies, the Socialist and Republican parties that are part of the government coalition currently leaving the Communists in a political wilderness. Although the criticism aired was general, and in the classic Communist impersonal fashion, much of it was said to be leveled at Natta's allegedly undistinguished leadership.